The fuel supply system supplies an appropriate air/
fuel mixture to the engine. There are the fuel tank,
fuel pump module assembly, and the fuel pipe that
couples each part. Engine malfunctions caused by
insufficient fuel supply or evaporative emission sys-
tem operation malfunctions can result from faults in
the vapor line, fuel pipe, hose, or fuel tank pressure
control valve, etc.

FUEL SUPPLY DIAGNOSTIC TROUBLESHOOTING STRATEGY

M1135004100039

Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will be sure that you
have exhausted most of the possible ways to find a
fuel supply fault.
1. Gather information from the customer.

2. Verify that the condition described by the

customer exists.

3. Find the malfunction by following the Symptom

Chart.

4. Verify malfunction is eliminated.

AC204062AB

FUEL PRESSURE
REGURATOR

FUEL ROLLOVER VALVE

FUEL LEVEL SENSOR

FUEL PUMP MODULE

LEVELING VALVE ASSEMBLY

EVAPORATIVE EMISSION
CANISTER

FUEL SUPPLY DIAGNOSIS

TSB Revision

FUEL SUPPLY

13B-3

SYMPTOM CHART

M1135004200188

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1:Engine Malfunctions Due to Insufficient Fuel Supply

TROUBLESHOOTING HINTS (The most likely causes for
this case:)

• Injector failed.

• Open or shorted injector circuit, or loose connector.

• Bent, kinked or clogged fuel pipe or hose.

• Malfunction of fuel pump module.

DIAGNOSIS

Required Special Tools:

• MB991502: Scan Tool (MUT-II)

• MB991637: Fuel Pressure Gauge Set

• MD998709: Adaptor Hose

• MD998742: Hose Adaptor

STEP 1. Using scan tool MB991502, read the diagnostic
trouble code (DTC).

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC is output?

YES : Refer to GROUP 13A, Diagnostic Trouble Code Chart

P.13Ab-22

NO : Go to Step 2.

SYMPTOM

INSPECTION PROCEDURE REFERENCE PAGE

Engine malfunctions due to insufficient fuel supply

P.13B-3

ACX01539

16-PIN

MB991502

FUEL SUPPLY DIAGNOSIS

TSB Revision

FUEL SUPPLY

13B-4

STEP 2. Check the fuel pressure.
(1) Release residual pressure from the fuel line to prevent fuel

spray. (Refer to

P.13Aa-15

WARNING

To prevent a fire, cover the hose connection with
shop towels to prevent splashing of fuel that could be
caused by some residual pressure in the fuel pipe
line.

(2) Disconnect the high-pressure fuel hose at the fuel rail side.
(3) Assemble the fuel pressure measurement tools as follows.

<When using the fuel pressure gauge>

Remove the union joint and bolt from special tool
MD998709 (adaptor hose) and instead attach special
tool MD998742 (hose adaptor) to the adaptor hose.

b. Place a suitable O-ring or gasket on assembled special

tools MD998709 and MD998742 and install the fuel
pressure gauge.

c. Install the assembled fuel pressure measurement tools

between the fuel rail and high-pressure fuel hose.

<When using the special tool MB991637 (fuel pressure

gauge set)>

Remove the union joint and bolt from special tool
MD998709 (adaptor hose) and instead attach special
tool MD998742 (hose adaptor) to the adaptor hose.

b. Install special tool MB991637 (fuel pressure gauge set)

to assembled special tools MD998709 and MD998742
via a gasket.

c. Install the assembled fuel pressure measurement tools

between the fuel rail and the high-pressure fuel hose.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(4) Connect scan tool MB991502 to the data link connector.
(5) Use the Actuator test 07 to drive the fuel pump. Check that

there is no fuel leaking from any section when the fuel
pump is operating.

(6) Stop the fuel pump.
(7) Start the engine and run at idle.
(8) Measure fuel pressure while the engine is running at idle.

Standard value: Approximately 270 kPa (38 psi) at
curb idle

AKX01456

HIGH-PRESSURE
FUEL HOSE

FUEL-
RAIL

AKX01457AB

FUEL PRESSURE
GAUGE

O-RING OR GASKET

MD998709

MD998742

HIGH-PRESSURE
FUEL HOSE

FUEL
RAIL

AKX01458

MB991637